The story starts with the orphan boy trying to find safety, leaving his country behind which has been destroyed by war. He tries to cross the ocean to get to another land but he's too small and too poor to cross. This is where the story gets murky in my memory - a dragon promises to help him if the orphan boy will work for him. Orphan boy agrees and is taken to the bottom of the ocean. The dragon makes orphan boy promise not to ask to see the dragon's daughter. Later, a cat with a blue umbrella, helps the orphan boy and later admits that she is the dragon's daughter. They run off and get married.
A funny thing is that I've asked some of my Hmong friends here about this story. There are Hmong stories about dragons and about orphan boys, and even the two together. But my Hmong friends decided that this story was "rewritten" in the US which is why they don't know it. And no one can think of any story which involves a white cat with a blue umbrella.